This invention relates to a hydraulic positioning system and more particularly to a hydraulic positioning system for selectively positioning a work machine attachment tool.
It is well known that a work machine, such as a skid steer loader, typically includes an attachment which is coupled to the work machine""s hydraulic system. These attachments typically include a tool which oftentimes is movable relative to the attachment""s frame. For example, a cold planer includes a rotary drum which oftentimes has laterally shifting, tilting and depth control capability effectuated by the use of a plurality of hydraulic cylinders. Traditionally, user control of the desired hydraulic cylinder consisted of running separate hydraulic lines from each cylinder to separate levers.
One prior art solution can be found in U.S. Pat. No. 5,299,857 issued to C. Christopher Zanetis on Apr. 5, 1994 which teaches the use of electro-hydraulic valves (E-H valves) to selectively control cylinder operation. In this design, a plurality of switch-activated E-H valves are mounted to a manifold located on the attachment""s frame and are used to divert hydraulic fluid from the work machine""s primary hydraulic lines to one of the secondary hydraulic lines coupling the manifold to a respective hydraulic cylinder. Although this design may be adequate for its intended purpose, the necessity for electronic components may lead to a more expensive and complex attachment then otherwise possible.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention, an attachment for a work machine having a primary hydraulic circuit for providing primary hydraulic pressure, and an auxiliary hydraulic circuit for providing auxiliary hydraulic pressure is provided. The attachment includes a frame adapted for coupling with the work machine, a tool coupled with the frame, a plurality of fluid cylinders operable to move the tool relative to the frame, and a fluid diverting device coupling the fluid cylinders to the auxiliary hydraulic circuit and being selectively positionable by the primary hydraulic pressure to divert the auxiliary hydraulic pressure to at least one of the fluid cylinders.
In another aspect of the present invention, a hydraulic positioning system for use with a work machine attachment having a frame and a tool is provided. The hydraulic positioning system includes a plurality of fluid cylinders coupling the tool with the frame, a fluid deflection device coupled to at least one fluid cylinder, an auxiliary hydraulic circuit having a fluid source and being in fluid communication with the fluid deflection device, and a primary hydraulic circuit in fluid communication with the fluid deflection device and operable to selectively deflect the fluid source of said auxiliary hydraulic circuit to at least one fluid cylinder.
In yet another aspect of the present invention, a method of operating a work machine attachment, said attachment including a frame and a tool, is provided. The method includes the steps of: providing at least a first fluid cylinder operatively coupling the tool with the frame; providing a fluid deflection device having a movable fluid deflection portion; coupling the primary hydraulic circuit to the fluid deflection device, the primary hydraulic circuit having a fluid pressure source; coupling the auxiliary hydraulic circuit to the fluid deflection device, the auxiliary hydraulic circuit having a fluid pressure source; and activating the fluid pressure source of the primary hydraulic circuit thereby causing movement of the movable fluid deflection portion so that the first fluid cylinder is in fluid communication with the auxiliary hydraulic circuit.